Introduction

The San Zi Jing (Three Character Classic), written in the 13th century and attributed to Wang Yinglin (1223-1296), is not one of the traditional six Confucian classics, but rather is a distillation of the essentials of Confucian thought expressed in a way suitable for teaching young children. Until the latter part of this century, it served as a child's first bit of formal education at home. It is written in couplets of three characters (syllables) for easy memorization. One might call it a Confucian catechism.

George Yeo, then Singapore's Minister for Trade and Industry, in an address at the Chinese University of Hong Kong, described the work thus: "For centuries, Chinese children, before they could read or write, were taught to recite the San Zi Jing through which the Confucianist idea of society being one big happy family is programmed into young minds. The three-character phrases are like strands of cultural DNA which are passed on from generation to generation." (Cf. Sanzijing at raptor.depauw.edu)

The San Zi Jing as appeared in the link you provided
http://www.pep.com.cn/200306/ca224428.htm
is actually a copy from
http://www.openface.ca/~dstephen/trimetric.htm

The person who put up the trimetric.htm page copied the text from Giles book by hand back in the late 1960s. He made several mistakes in his transcription which he could not decipher when he put his Web page a few years ago. The "side-notes" of the undecipherable text showed up as "distinct markers" whenever someone else reprints
the material from his site.
So far, all the reprints of the Giles version on the Web has been traced back to the same source.